Summary:
As far as I can tell, doing our own computations in
NearestCommonDominator is a false optimization -- DomTree will build up
what appears to be exactly this data when it decides it's worthwhile.
Moreover, by building the cache ourselves, we cannot take advantage of
the cache that the domtree might have available.
In addition, I am not convinced of the correctness of the original code.
In particular, setting ResultIndex = 1 on the first addBlock instead of
setting it to 0 is quite fishy. Similarly, it's not clear to me that
setting IndexMap[Node] = 0 for every node as we walk up the tree finding
a common parent is correct. But rather than ponder over these
questions, I'd rather just make the code do the obviously-correct thing.
This patch also changes the NearestCommonDominator API a bit, improving
the names and getting rid of the boolean parameter in addBlock -- see
http://jlebar.com/2011/12/16/Boolean_parameters_to_API_functions_considered_harmful..html
Reviewers: arsenm
Subscribers: aemerson, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D26998
llvm-svn: 288050
At the moment optimized tablegen is generated by LLVM_USE_HOST_TOOLS variable that is not set for Visual Sudio since LLVM_ENABLE_ASSERTIONS depends on CMAKE_BUILD_TYPE value that is not equal to "DEBUG" in case of Visual Studio soltion generation.
Modified to do not depend on LLVM_ENABLE_ASSERTIONS value in VS and Xcode cases
Reviewers: beanz
Subscribers: RKSimon, llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D27135
llvm-svn: 288042
Bit-shifts by a whole number of bytes can be represented as a shuffle mask suitable for combining.
Added a 'getFauxShuffleMask' function to allow us to create shuffle masks from other suitable operations.
llvm-svn: 288040
This adds assembler support for the instructions provided by the
execution-hint facility (NIAI and BP(R)P). This required adding
support for the new relocation types for 12-bit and 24-bit PC-
relative offsets used by the BP(R)P instructions.
llvm-svn: 288031
This patch adds assembler support for the remaining branch instructions:
the non-relative branch on count variants, and all variants of branch
on index.
The only one of those that can be readily exploited for code generation
is BRCTH (branch on count using a high 32-bit register as count). Do
use it, however, it is necessary to also introduce a hew CHIMux pseudo
to allow comparisons of a 32-bit value agains a short immediate to go
into a high register as well (implemented via CHI/CIH).
This causes a bit of codegen changes overall, but those have proven to
be neutral (or even beneficial) in performance measurements.
llvm-svn: 288029
This patch moves formation of LOC-type instructions from (late)
IfConversion to the early if-conversion pass, and in some cases
additionally creates them directly from select instructions
during DAG instruction selection.
To make early if-conversion work, the patch implements the
canInsertSelect / insertSelect callbacks. It also implements
the commuteInstructionImpl and FoldImmediate callbacks to
enable generation of the full range of LOC instructions.
Finally, the patch adds support for all instructions of the
load-store-on-condition-2 facility, which allows using LOC
instructions also for high registers.
Due to the use of the GRX32 register class to enable high registers,
we now also have to handle the cases where there are still no single
hardware instructions (conditional move from a low register to a high
register or vice versa). These are converted back to a branch sequence
after register allocation. Since the expandRAPseudos callback is not
allowed to create new basic blocks, this requires a simple new pass,
modelled after the ARM/AArch64 ExpandPseudos pass.
Overall, this patch causes significantly more LOC-type instructions
to be used, and results in a measurable performance improvement.
llvm-svn: 288028
In r286814, the algorithm for calculating inline costs changed. This
caused more inlining to take place which is especially apparent
in optsize and minsize modes.
As the cost calculation removed a skewed behaviour (we were inconsistent
about the cost of calls) it isn't possible to update the thresholds to
get exactly the same behaviour as before. However, this threshold change
accounts for the very common case where an inline candidate has no
calls within it. In this case, r286814 would inline around 5-6 more (IR)
instructions.
The changes to -Oz have been heavily benchmarked. The "obvious" value
for the inline threshold at -Oz is zero, but due to inaccuracies in the
inline heuristics this can actually cause code size increases due to
not inlining key thunk functions (that then disappear). Experimentally,
5 was the sweet spot for code size over the test-suite.
For -Os, this change removes the outlier results shown up by green dragon
(http://104.154.54.203/db_default/v4/nts/13248).
Fixes D26848.
llvm-svn: 288024
This never made a lot of sense. They've been invalidated for one IR unit
but they aren't really preserved in any normal sense. It seemed like it
would be an elegant way of communicating to outer IR units that pass
managers and adaptors had already handled invalidation, but we've since
ended up adding sets that model this more clearly: we're now using
the 'AllAnalysesOn<IRUnitT>' set to handle cases where the trick of
"preserving" invalidated analyses didn't work.
This patch moves to rely on that technique exclusively and removes the
cumbersome API aspect of updating the preserved set when doing
invalidation. This in turn will simplify a *number* of upcoming patches.
This has a side benefit of exposing a number of places where we were
failing to mark the 'AllAnalysesOn<IRUnitT>' set as preserved. This
patch fixes those, and with those fixes shouldn't change any observable
behavior.
llvm-svn: 288023
Some scanner errors were not checked and reported by the parser.
Fix PR30934
Patch by: Serge Guelton <serge.guelton@telecom-bretagne.eu>
Differential Revision: https://reviews.llvm.org/D26419
llvm-svn: 288014
I don't think isel selects these today, favoring adding the register to itself instead. But the load folding tables shouldn't be so concerned with what isel will use and just represent the relationships.
llvm-svn: 288007
Note that the non-splat lshr+lshr test folded, but that does not
work in general. Something is missing or wrong in computeKnownBits
as the non-splat shl+shl test still shows.
llvm-svn: 288005
If we were to unfold these, the load size would be increased to the register size. This is not safe to do since the enlarged load can do things like cross a page boundary into a page that doesn't exist.
I probably missed some instructions, but this should be a large portion of them.
llvm-svn: 288001
Most of these are the SSE4.1 PMOVZX/PMOVSX instructions which all read less than 128-bits. The only other was PMOVUPD which by definition is an unaligned load.
llvm-svn: 287991
Summary: When selectScalarSSELoad is looking for a scalar_to_vector of a scalar load, it makes sure the load is only used by the scalar_to_vector. But it doesn't make sure the scalar_to_vector is only used once. This can cause the same load to be folded multiple times. This can be bad for performance. This also causes the chain output to be duplicated, but not connected to anything so chain dependencies will not be satisfied.
Reviewers: RKSimon, zvi, delena, spatel
Subscribers: andreadb, llvm-commits
Differential Revision: https://reviews.llvm.org/D26790
llvm-svn: 287983
There are other spots where we can use this; we're currently dropping
metadata in some places, and there are proposed changes where we will
want to propagate metadata.
IRBuilder's CreateSelect() already has a parameter like this, so this
change makes the regular 'Create' API line up with that.
llvm-svn: 287976
